The present invention relates to improvements in helical cutterheads, particularly cutterheads such as those shown in my prior U.S. Pat. No. 4,074,737, the entire disclosure of which is incorporated herein by reference.
My prior patent discloses a helical cutterhead for a planer having a particular pitch arrangement to reduce the noise generated by the cutterhead while planing a workpiece. The cutterhead has a plurality of segmented cutterhead inserts, each of which includes a cutting blade mounted in cooperating or receiving grooves in the cutterhead body. In a typical arrangement, the cutterhead inserts span about one inch along the cutterhead length. The cutterhead inserts are securely mounted in the grooves to form a substantially continuous cutting edge. As set forth in that patent, the contour of the actual cutting edge of the blades preferably follows the contour of the helical groove in the cutterhead.
In one embodiment described in the '737 patent, the cutterhead inserts have carbide cutting blades brazed or welded to them. The carbide blade, after brazing to the cutterhead insert, is subsequently ground to obtain a helical geometry in keeping with the entire helix of the cutterhead. When the cutting blade is worn out, the entire cutterhead insert must be replaced or returned to a toolshop for retipping and regrinding.
In the prior art cutterheads, the brazing method of attachment limits the materials which can be used as the cutting blades to those that can withstand brazing, such as conventional carbide. However, more advanced cutting materials including diamonds, ceramics, coated materials, etc. would be difficult to braze and impractical to use as the entire cutterhead insert.
Thus, there is a need in the art for a cutterhead insert that permits other blade materials to be used to form the cutting edge, as well as increases the flexibility and ease of replacement of blades as they are worn or damaged.